What does the exportObject of UnicastRemoteObject do?
Exports
the remote object to make it available to receive incoming calls, using the
particular supplied port. If port not specified receives calls from any
anonymous port.
What is PortableRemoteObject.narrow() method and what is
used for?
Java RMI-IIOP provides a
mechanism to narrow the the Object you have received from from your lookup, to
the appropriate type. This is done through the javax.rmi.PortableRemoteObject
class and, more specifically, using the narrow() method.
In a RMI Client Program, what are the excpetions which might have to handled?
a. MalFormedURLException
b. NotBoundException
c. RemoteException
What is RMI?
Remote Method Invocation (RMI) is the process of activating a
method on a remotely running object. RMI offers location transparency in the
sense that it gives the feel that a method is executed on a locally running
object.
What is the basic principle of RMI
architecture?
The RMI architecture is based on one important principle: the
definition of behavior and the implementation of that behavior are separate
concepts. RMI allows the code that defines the behavior and the code that
implements the behavior to remain separate and to run on separate JVMs.
What are the layers of RMI
Architecture?
The RMI is built on three layers.
a. Stub and Skeleton layer
This layer lies just beneath the view of the developer. This layer
intercepts method calls made by the client to the interface reference variable
and redirects these calls to a remote RMI service.
b. Remote Reference Layer.
This layer understands how to interpret and manage references made
from clients to the remote service objects. The connection is a one-to-one
(unicast) link.
c. Transport layer
This layer is based on TCP/IP connections between machines in a
network. It provides basic connectivity, as well as some firewall penetration
strategies.
What is the role of Remote Interface in RMI?
The Remote interface serves to identify interfaces whose methods
may be invoked from a non-local virtual machine. Any object that is a remote
object must directly or indirectly implement this interface. Methods that are
to be invoked remotely must be identified in Remote Interface. All Remote
methods should throw RemoteException.
What is the role
java.rmi.Naming Class?
The Naming class provides methods for storing and obtaining
references to remote objects in the remote object registry.
What is the default
port used by RMI Registry?
1099
What is meant by binding
in RMI?
Binding is a process of associating or registering a name for a
remote object that can be used at a later time to look up that remote object. A
remote object can be associated with a name using the Naming class's bind or
rebind methods.
What is the difference between
using bind() and rebind() methods of Naming Class?
bind method(String name) binds the specified name to a remote
object while rebind(String name) method rebinds the specified name to a new
remote object,any existing binding for the name is replaced.
When is AlreadyBoundException
thrown and by which method?
AlreadyBoundException is thrown by bind(String name) method when a
remote object is already registered with the registry with the same name.
Note: rebind method doesn't throw AlreadyBoundException because it
replaces the existing binding with same name.
How to get all the
registered objects in a rmiregistry?
Using list method of Naming Class.
Can a class implementing
a Remote interface
have non remote methods?
Yes. Those methods behave as normal java methods operating within
the JVM.
What is the protocol
used by RMI?
JRMP(java remote method protocol)
What is the use
of UnicastRemoteObject
in RMI?
The UnicastRemoteObject class provides support for point-to-point
active object references using TCP streams. Objects that require remote
behavior should extend UnicastRemoteObject.
What
does the exportObject of UnicastRemoteObject do?
Exports the remote object to make it available to receive incoming
calls, using the particular supplied port. If port not specified receives calls
from any anonymous port.
What is PortableRemoteObject.narrow()
method and what is used for?
Java RMI-IIOP provides a mechanism to narrow the the Object you
have received from from your lookup, to the appropriate type. This is done
through the javax.rmi.PortableRemoteObject class and, more specifically, using
the narrow() method.
In a RMI Client Program,
what are the excpetions
which might have to handled?
a. MalFormedURLException
b. NotBoundException
c. RemoteException
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